title: Serum interleukin-6 concentration reflects the extent of asymptomatic left ventricular dysfunction and predicts progression to heart failure in patients with stable coronary artery disease.
abstract: BACKGROUND
  Left ventricular ejection fraction (LVEF) remains one of the strongest predictors of long-term prognosis in patients with stable coronary artery disease (CAD). Asymptomatic left ventricular systolic dysfunction (LVSD) often precedes clinically overt heart failure (HF) and is an area of extensive research nowadays. We studied the association between serum IL-6 concentrations and the extent of LV dysfunction in patients with asymptomatic LVSD. We aimed to investigate the diagnostic value of serum IL-6 concentrations in predicting the risk of progression to HF. Seventy-one patients entered the study and were divided into three groups based on LVEF: group 1 - patients with LVEF <30% (N=7), group 2 - patients with LVEF 30-50% (N=37) and group 3 - patients with LVEF >50% (N=27).
  
  
  RESULTS
  Demographics were similar in all three groups. IL-6 concentration was the highest in group 1 (median 8.6 pg/mL) and the lowest in group 3 (median 2.6 pg/mL), whereas IL-6 concentration in group 2 was intermediate (median 3.7 pg/mL) (P=0.002). We found a significant, inverse correlation between IL-6 concentration and ejection fraction. During 18-month follow-up clinically overt HF developed in 71.4% of patients in group 1 and in 37.5% of patients in group 2. None of the patients in group 3 manifested HF symptoms (P<0.001). ROC analysis revealed high diagnostic value of serum IL-6 and LVEF in predicting progression to HF. We also found a strong, inverse correlation between IL-6 and the time of progression to HF.
  
  
  CONCLUSIONS
  There is a strong correlation between IL-6 and the extent of asymptomatic LVSD in patients with documented CAD. Elevated IL-6 concentrations preceded progression to clinically overt HF. Moreover, the higher the IL-6 concentration the earlier the manifestation of HF symptoms.
authors.affiliation: Third Department of Cardiology, Silesian Center for Heart Disease, Silesian Medical University, Szpitalna 2, 41-800 Zabrze, Poland. bartekh@mp.pl
authors.forename: Bartosz
authors.initials: B
authors.lastname: Hudzik
authors.forename: Janusz
authors.initials: J
authors.lastname: Szkodzinski
authors.forename: Wojciech
authors.initials: W
authors.lastname: Romanowski
authors.forename: Aleksander
authors.initials: A
authors.lastname: Danikiewicz
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Wilczek
authors.forename: Andrzej
authors.initials: A
authors.lastname: Lekston
authors.forename: Lech
authors.initials: L
authors.lastname: Polonski
authors.forename: Barbara
authors.initials: B
authors.lastname: Zubelewicz-Szkodzinska
mesh_terms: D000368:Aged; D002309:Cardiology / Q000379:methods; D018450:Disease Progression; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006333:Heart Failure; D006801:Humans; D015850:Interleukin-6 / Q000097:blood* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012372:ROC Curve; D012306:Risk; D012680:Sensitivity and Specificity; D018487:Ventricular Dysfunction, Left / Q000097:blood* / Q000175:diagnosis
chemical_list: D015850:Interleukin-6